NOTICE: As of the release of HEC-HMS version 4.8 in April 2021, there is no longer a requirement that modelers use HEC-GeoHMS to delineate elements for an HEC-HMS project. HEC-HMS includes GIS tools that allow modelers to delineate elements, define a discretization, compute subbasin and reach characteristics, and estimate model parameters. The HEC-HMS team is no longer investing resources in developing, testing, and supporting HEC-GeoHMS. Instead, effort will continue be directed at improving and adding GIS capabilities directly to the HEC-HMS software. You can read about the HEC-HMS GIS tools here, https://www.hec.usace.army.mil/confluence/hmsdocs/hmsum/latest/geographic-information. Workshops with example datasets can be found here, https://www.hec.usace.army.mil/confluence/pages/viewpage.action?pageId=42175930.

HEC-GeoHMS is a GIS extension that provides the user with a set of procedures, tools, and utilities for the preparation of GIS data for import into HEC-HMS and generation of GIS data from HMS output. While the GeoHMS extension is designed for users with limited geographic information systems (GIS) experience, knowledge of GIS is advantageous. Users, however, must have experience modeling with HEC-HMS and have a thorough understanding of hydrology to properly create and interpret GIS data sets.